Hyperactive behavior (HB) is a vexing problem for a large number of children with and without a formal diagnosis of attention-deficit/ hyperactivity disorder(ADHD). Although the causes of HB are poorly understood, one such cause may be primary sleep disorders; the small subset of children seen at sleep centers often have HB that resolves when a sleep disorder is identified and treated. Arising from this observation, our long-term objective is to examine the impact of undiagnosed sleep disorders on HB in children. We will use a cross-sectional survey of 1000 parents at a general pediatrics clinic to identify hyperactive children aged 2 to 14 years. We will perform clinical and polysomnographic evaluations of 90 such children to establish the frequency of sleep disorders. A randomized controlled clinical trial will be performed with at least 20 subjects to determine whether HB improves when children's sleep disorders are treated. These studies will define the frequency, significance, and therapeutic implications of primary sleep disorders in hyperactive children and will test the hypothesis that primary sleep disorders are and important cause of HB.